This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-331125, filed Oct. 30, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a suspension for disc drive incorporated in an information processing apparatus, such as a personal computer.
A hard disc drive (HDD) for recording in and reading information from a rotating magnetic disc or magneto-optical disc includes a carriage that can turn around a shaft. The carriage is rotated around the shaft by means of a positioning motor. The carriage is provided with an arm (actuator arm), a suspension mounted on the distal end portion of the arm, a head portion including a slider mounted on the suspension, etc.
When the disc rotates, the slider on the distal end portion of the suspension slightly lifts off the disc surface, whereupon an air bearing is formed between the disc and the slider. The suspension comprises a base portion including a base plate, a beam portion formed of a precision plate spring, a flexure fixed to the beam portion by laser welding or the like, etc.
With the advance of compaction of information recorded in the disc and speed-up of the disc drive operation, the disc drive of this type has been requiring a shorter seek time. In order to shorten the seek time, the disc rotation must be speeded up.
The flexure is formed into various shapes according to required specifications. By way of example, a so-called wired flexure has been developed such that a wiring portion is formed along a beam portion on the surface of a flexure that extends in the longitudinal direction of the beam portion. One end of the wiring portion of the wired flexure is connected to a terminal of the slider at the distal end portion of the flexure. The other end of the wiring portion extends toward the proximal portion of the beam portion, and is connected to a terminal closer to an actuator, for example.
If a wired flexure that partially crosses an edge portion of a beam portion swings under the influence of air turbulence that is caused over the surface of a rotating disc, the flexure may possibly touch the beam portion. Depending on the shape of the edge portion of the beam portion, a contact portion between the beam portion and the flexure may be fretted, possibly causing contamination (with minute contaminants).
Accordingly, the object of the present invention is to provide a suspension capable of avoiding an awkward situation that may be caused when an attachment such as a flexure that is attached to a beam portion touches the beam portion.
In order to achieve the above object, a suspension for disc drive in a first aspect of the present invention comprises a beam portion having an edge portion and an attachment attached to the beam portion so as to be superposed thereon and having an extending portion extending across the edge portion of the beam portion, in which the edge portion of the beam portion crossed by the extending portion is formed having a chamfered portion for preventing fretting such that the edge portion is reduced in thickness so that the distance from the extending portion gradually increases toward an end face of the edge portion. According to this invention, the attachment can be prevented from touching a sharp edge of the edge portion of the beam portion when it swings, so that contamination can be avoided. Thus, the invention is also applicable to a disc drive in which a disc rotates at high speed.
In order to achieve the above object, a suspension for disc drive in a second aspect of the invention comprises a base portion, a beam portion having an edge portion, a hinge member connecting the base portion and the beam portion to each other, and an attachment attached to the beam portion so as to be superposed thereon and having an extending portion extending across the edge portion of the beam portion, in which the edge portion of the beam portion crossed by the extending portion is formed having a chamfered portion such that the edge portion is reduced in thickness so that the distance from the extending portion gradually increases toward an end face of the edge portion. In the suspension according to this invention designed so that the base portion and the beam portion are connected to each other by means of the hinge member, the attachment can be prevented from touching a sharp edge of the edge portion of the beam portion when it swings, so that contamination can be avoided. Thus, the invention is also applicable to a disc drive in which a disc rotates at high speed.
In each of the suspensions in the first and second aspects, an example of the attachment is a wired flexure. If the wired flexure swings under the influence of air turbulence or the like, occurrence of contamination that may be caused when the flexure touches the edge of the beam portion can be avoided. However, the chamfered portion may be formed on any other attachment than the flexure, e.g., the edge of the beam portion that is crossed by a wiring member. Further, the chamfered portion may be formed on any other edge portion than the side edge portion of the beam portion. In short, the chamfered portion should only be formed on an edge portion that is expected to touch the attachment.
The chamfered portion may be formed by plastically deforming a part of the edge portion of the beam portion by coining, a kind of pressing, for example. According to this invention, the chamfered portion formed by coining has a smooth surface. Alternatively, the chamfered portion may be formed by partially etching the edge portion of the beam portion. According to this invention, the chamfered portion can be easily formed by partial etching.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.